1. Field of the Art
The present invention relates to the art of biology and agriculture and, more particularly, to a method of sterilizing anthers of plants which is used in selection and seed production.
2. Description of the Prior Art
At the present time the world is facing the problem of intensification of agriculture, in particular of raising yields of grain crops, fodder, vegetable and industrial plants by way of an extensive application of the first-generation hybrids. Due to the heterosis phenomenon these hybrids are distinguished from the parental forms by a higher (by 25-30%) productivity and a better quality of the products. Known is a method for breeding novel hybrids which is based on a "cytoplasmic male sterility-fertility reductants" system. This method is based on a long-term (12-14 years) and complicated selection work involving the creation of sterile analogs, sterility-fixing agents and fertility reductants. Most promising are methods based on sterilization of anthers of plants by chemical sterilizing agents (gametocides). The use of gametocides proves to be much more economically efficient than the use of the "cytoplasmic male sterility" system, since there is no necessity in creating such forms as a sterile analog, an analog of sterility fixation in maternal forms and an analog of fertility reduction in paternal ones. In fact it is possible to obtain seeds of the first-generation hybrids both in the course of the selection studying of the initial forms and in the organization of their industrial production.
By now about 200 compounds have been found which display a gametocidal activity and belong to different classes of chemical compounds as regards their chemical structure. Gametocides must cause maximum full male sterility in the treated plants, while preserving the viability of ovicells and ensuring settability in free pollination at a sufficiently high level (preferably not less than 70% of the control). Their phytotoxicity and toxicity for the warm-blooded must be minimal.
Known in the art are methods of sterilizing the anthers of gramineous crops (L. J. Nickell. Plant Growth Regulators. Applications in Agriculture. Moscow, "Kolos" Publishers, 1984, pp. 28-31; SU, A, No. 906457) which comprise treating the plants with sterilizing agents such as 2-chloroethylphosphonic acid (Ethrel), maleic acid hydrazide, di-(polyfluoroalkyl)-phosphoric acids and salts thereof and the like. The treatment of the plants with the sterilizing agents is effected at the V-th or VI-th stage of organogenesis (after F. M. Kuperman).
At the V-th stage of organogenesis the processes of the formation and differentiation of florets begin. At the end of this stage neoplasms originate: sporogeneous archisporeal tissues. At this stage the initiation of stamina, pistil and integumentary organs of the floret occurs. At the V-th stage the beginning of differentiation of the stamen primordium into a connective and pistil is observed. The VI-th stage is characterized by the processes of the floret formation (micro- and macro-sporogenesis). At this stage individual mononuclear pollen grains are usually formed (F. M. Kuperman, "Morphophysiology of Plants", Moscow, "Vysshaya Shkola" Publishers, 1973, pp. 30-36).
Also known in the art is a method of sterilizing the anthers of gramineous plants (GB, A, No. 1567153), which comprises treating the gramineous plants with a sterilizing agent during the period between the appearance of the second internode and earing. As the sterilizing agent use is made of heterocyclic compounds, the main representatives thereof being 2-carboxy-3,4-methanopyrrolidine or 2-methoxycarbonyl-3,4-methanopyrrolidine. These compounds are used in combination with diluents and surfactants.